You may claim lost wages that result from an automobile accident against your disability insurance policy. Contact your insurance representative to submit a claim that describes how the injury rendered you unable to work.
If your lost wages are related to an injury, you will need to have documentation from your doctor to confirm you were unable to perform your job. You should keep track of the dates/time missed for doctor and/or therapy appointments, which can then be corroborated with your medical records. Tax records will be needed to substantiate your claim.
In order to do this you will have to prove your previous income through either tax returns or a cash flow. Without this information you will not be able to claim lost wages.
You need to have proof of your self-employment income. This can be reciepts or any other paperwork (tax documents, for example). You can also provide any contracts that you were not able to fulfill because of your injury.
Depending on the liability scenario, this claim could be handled differently. Either way, provide your insurer your W-2's showing your annual wage, or a bi-weekly pay stub if you pay yourself. Either of these should allow for sufficient information to investigate and pay your claim.